Fascinators — the headpieces often worn by women to weddings in the U.K. — perched on well-coiffed heads, while red, blue and white British flags were draped around shoulders and children wore blow-up crowns.

The crowd was preparing for a ceremony set for noon local time (7 a.m. ET) at St. George's Chapel inside of Windsor Castle.

Four miles of bunting decorated the town and royal fans staked out spaces along the processional route days before the ceremony to ensure a good view.

By 6:30 a.m. (1:30 a.m. ET), the sidewalk nearest to castle was becoming unpassable as good-natured crowds tried to get as close as possible to the wedding venue.

Toni Shah, 43, of Ann Arbor, Michigan, was not taking any chances and spent Friday night sleeping on the procession route instead of at a hotel she and her husband Rick had booked months ago.

"I want to be front-and-center," she said.

While Shah said she has long been a fan of the royals — "I've read all the books, watched every movie" — Markle was a particular draw.

Rick and Toni ShahF. Brinley Bruton

"I'm going to wave my American flag supporting her — that's the first thing," Shah said after a chilly night wrapped tightly in a sleeping bag. "I think I'll probably be crying to be quite honest."

Shah said that Markle "represents change," adding: "I like that she's the new Britain: She's American, she's an actress, she's a minority."

Screens were set up along the Long Walk leading up to Windsor Castle and in the Alexandra Gardens park so well-wishers could watch the ceremony together.

The newlyweds were scheduled to take a carriage ride through town to greet the public. Estimated to last around 25 minutes, Markle and Harry — who will officially be known as the Duke and Duchess of Sussex — will ride in an open-topped Ascot Landau carriage pulled by four horses.

"The officers on the ground are there to protect the public and keep the public safe, but also if anything were to happen then we're ready to be able to respond to anything," said Thames Valley Police Commander David Hardcastle, who is coordinating the security operation.

To help accommodate the large numbers of visitors, bus and rail companies added extra train and bus services.